The router is reset to factory settings after a while. How to fix?

Question

network hardware

I have a Dlink-815s router. A couple of years ago I took it from Beeline with a ransom, then lay around in a box idle. Now I found an application, set it up, but after some time (1-2 hours) I observe that the light is on red, there is no Internet. Then I saw that the router simply resets the settings to factory settings. It also has firmware version 1.0.1, although on the website and on the Beeline website in the characteristics of this router is 3.0.0, however, when updating, it gives out the type "file is damaged", downloaded both firmware, installed both from the phone and from the laptop, everywhere the problem is the same. Through the lan port is also not flashed. Where to dig?

Answer 1

It may not be possible to flash version 1 immediately to 3, you need to use intermediate 2.
Try to find version 2 of the firmware and flash it first, and then upgrade 2 to 3.
You can also look for a suitable unofficial firmware, maybe there are such for your router.

Answer 2

most likely it is reset by the autoscript of the beeline ...
check the proto, as they said above, set up that thread and leave it to work, but without a WAN cable,
if it resets, it’s most likely easier to go to the trash